Corner formative member, and apparatus for chamfering apex angle portion of corner formative member

ABSTRACT

A corner formative member A includes at least two plate pieces  1   a  and  1   a  bonded with each other at side portions thereof via reactive hot melt adhesive P so as to form an apex angle portion  3  extending in a longitudinal direction. A chamfered portion  8  with a narrow width is formed on the apex angle portion  3.  The chamfered portion  8  is formed into a longitudinally extended non-horizontal irregularly arranged continuous concavo-convex surface. An adhesive layer P remains at a joint portion of the apex angle portion  3  and an end face of the adhesive layer P at the chamfered portion side is a flat surface along the concavo-convex surface of the chamfered portion  8.  An apparatus B for chamfering the apex angle portion  3  of the corner formative member A includes a corner formative member supporting means  20  for supporting the corner formative member A, a rotation cutting tool  30  disposed so as to intersect with the apex angle portion  3,  a rotation cutting tool supporting means  20  for supporting the rotation cutting tool  30  in a vertically movable manner along a concavo-convex surface formed at the apex angle portion  3,  a transporting means  21  for giving a relative movement between the rotation cutting tool  30  and the corner formative member A, and a cooling means  50  for cooling a region where the apex angle portion  3  is cut with the rotation cutting tool  30.

This application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2005-155563 filed on May 27, 2005, the entire disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a corner formative member used for an external material for an external corner portion of a building wall surface, and an apparatus for chamfering an apex angle portion of the corner formative member.

2. Description of the Related Art

The following description sets forth the inventor's knowledge of related art and problems therein and should not be construed as an admission of knowledge in the prior art.

In general, as an external material used for an external corner portion of a building wall surface, a corner formative member A as shown in FIG. 9 is known (see, e.g., Japanese Unexamined Laid-open Patent Publication No. H11-188294, hereinafter referred to as “Patent Document 1”). Such corner formative member A is usually manufactured by, as shown in FIG. 10(a), cutting, e.g., a fiber reinforced cement siding construction panel 1 having a surface pattern (not illustrated) into plate pieces 1 a and 1 a each having a certain width, cutting one side of each plate piece obliquely (usually at an angle of 45°, but not limited to it) (see FIG. 10(b)), and bonding the cut surfaces with each other to form an apex angle portion 3 (see FIG. 10(c)).

At the time of the manufacturing, misalignment may occur at the apex angle portion 3 and/or the adhesive used for the bonding may overflow from the apex angle portion 3. Therefore, for the purpose of, e.g., removing the overflowed adhesive, chamfering work is executed on the apex angle portion 3 with a mechanical means, such as, e.g., a Tenoner cutting machine, to thereby form a chamfered portion 4 (see FIG. 10(d)). Conventional chamfering work using a Tenoner cutting machine results in a chamfered portion 4 with a wide flat face about 10 to 20 mm in width and different from the surface of the plate piece 1 a in color. Therefore, post-painting is separately performed using an apparatus as disclosed in Patent document 1.

As the adhesive used for the bonding, humidity hardening type urethane or epoxy system adhesive is widely used. However, such a humidity hardening type adhesive takes a longer time for the hardening and therefore it is poor in productivity. Thus, in place of such adhesive, reactive hot melt adhesive capable of demonstrating a prescribed bonding effect in a short period of time is sometimes used for manufacturing a corner formative member (see Japanese Unexamined Laid-open Patent Publication Nos. H09-256594 and 2003-232117, hereinafter referred to as “Patent Document 2” and “Patent Document 3,” respectively).

As mentioned above, in a conventional corner formative member, chamfering work is executed to the apex angle portion using an apparatus, such as a Tenoner cutting machine, and therefore the chamfered portion 4 becomes a flat face with a wide width. Under such circumstances, even if the chamfered portion 4 is painted later (i.e., post-painting), it can be easily recognized. Moreover, since the chamfered portion 4 is a flat plane continuously extending in the longitudinal direction, the shade of the portion looks inevitably different from that of the remaining surface pattern.

Moreover, in cases where reactive hot melt adhesive is used to improve the productivity, frictional heat generated between the adhesive and the rotation cutting tool at the time of the chamfering work causes melting of the surface portion of the reactive hot melt adhesive (normally at the softening point of 80 to 90° C.), resulting in cutting of the surface portion of the softened adhesive with the rotation cutting tool, which in turn causes adhesion of the very thinly cut pieces to the cut surface. As a result, as schematically shown in FIG. 11, minute irregularities Pd may sometimes be generated on the end face Pc of the adhesive layer P at the surface of the chamfered portion 4. These irregularities Pd will be in a rough or shaggy state. Such minute irregularities Pd affect a surface of a coating layer to be formed by post-painting, which also causes the difference between the shade of the chamfered portion and that of the remaining surface pattern. Another problem is that the re-softened reactive hot melt adhesive clings to the rotation cutting tool during the cutting work.

The description herein of advantages and disadvantages of various features, embodiments, methods, and apparatus disclosed in other publications is in no way intended to limit the present invention. For example, certain features of the preferred embodiments of the invention may be capable of overcoming certain disadvantages and/or providing certain advantages, such as, e.g., disadvantages and/or advantages discussed herein, while retaining some or all of the features, embodiments, methods, and apparatus disclosed therein.

SUMMARY OF THE INVENTION

The preferred embodiments of the present invention have been developed in view of the above-mentioned and/or other problems in the related art. The preferred embodiments of the present invention can significantly improve upon existing methods and/or apparatuses.

Among other potential advantages, some embodiments can provide a corner formative member with a less noticeable chamfered portion on an apex angle portion formed by bonding cut surfaces of plate pieces each having an embossed pattern as a surface pattern extending in a direction intersecting with a joint portion of the plate pieces.

Among other potential advantages, some embodiments can provide a corner formative member with a stabilized chamfered portion for post-painting having no minute irregularity obtained by preventing re-softening of adhesive due to friction heat thereby causing less strange appearance even in the case of using reactive hot melt adhesive for bonding to enhance the productivity.

Among other potential advantages, some embodiments can provide an apparatus for chamfering an apex angle portion of the aforementioned corner formative member.

According to a first aspect of some preferred embodiments of the present invention, a corner formative member, comprises:

at least two plate pieces bonded with each other at side portions thereof via reactive hot melt adhesive so as to form an apex angle portion extending in a longitudinal direction,

wherein a chamfered portion with a narrow width is formed on the apex angle portion,

wherein the chamfered portion is formed into a longitudinally extended non-horizontal irregularly arranged continuous concavo-convex surface, and

wherein an adhesive layer remains at a joint portion of the apex angle portion and an end face of the adhesive layer at the chamfered portion side is a flat surface along the concavo-convex surface of the chamfered portion.

In the present invention, as the plate piece for the corner formative member, a plate piece with a certain width obtained by cutting, e.g., a conventionally known fiber reinforced cement siding system construction panel can be used. Reactive hot melt adhesive is preferably used for the bonding of the two plate pieces. With this, a period of time for obtaining prescribed boding strength can be shortened, resulting in improved productivity. The reactive hot melt adhesive to be used is not specifically limited. For example, conventionally known reactive hot melt adhesive (more specifically, reactant polyurethane system hot melt adhesive), such as, e.g., polyisocyanate and polyol, can be used suitably.

In the corner formative member according to the present invention, a chamfered portion with a narrow width is formed on the apex angle portion. The chamfered portion is not a longitudinally continued horizontal plane formed by chamfering using an apparatus such as a Tenoner cutting machine, but an irregular continuous concavo-convex surface. Therefore, the chamfered portion formed on the apex angle portion becomes less conspicuous as compared with a conventional horizontally flat chamfered portion with a wide width, which improves the design appearance of the corner formative member. Furthermore, it also becomes possible to produce a shade similar to a shade generated on the surface pattern portion of the plate piece on the chamfered portion.

Furthermore, as will be explained later, in manufacturing the corner formative member according to the present invention, the chamfering work of the apex angle portion is performed while cooling. Therefore, the reactive hot melt adhesive used for the bonding would not be re-softened by the frictional heat by the rotation cutting tool. Therefore, the end face (exposed surface) of the adhesive layer remaining at the joint portion of the apex angle portion at the side of the chamfered portion is a flat face extending along the concavo-convex surface of the chamfered portion. Since conventional minute irregularities have not been formed on the end face (exposed surface) of the adhesive layer, the coating surface to be formed by post-painting will become stable. This also does not disturb the shade on the chamfered portion.

As the plate piece, it is preferable to use a plate piece having an embossed pattern as a surface pattern extending in a direction intersecting with a joint face. More specifically, the embossed pattern has a plurality of convex ridges and concave grooves arranged alternatively and extending in a direction perpendicular to the joint face. In this case, all of the convex ridges and the concave grooves can be the same in shape. Alternatively, it can be configured such that some of them are the same in shape but the others are different. From the viewpoint of the appearance design, the latter is preferably employed. In this case, the embossed pattern can be formed on the entire surface of the plate piece, or another patter can be included at a part thereof.

In that case, the height of the embossed pattern extending in a direction intersecting with the joint face from the lowest concave portion to the highest convex portion, i.e., the distance from the bottom of the concave groove to the apex of the convex ridge, is not specifically limited. However, in view of the practical thickness and the appearance design of the plate piece, it is practical to be about 15 mm or less. Moreover, the distance between the adjacent apexes of the embossed patterns extending in a direction intersecting with the joint face, i.e., the distance between the adjacent apexes of the convex ridges, is preferably about 30 mm or less, more preferably about 5 to 20 mm, from the viewpoint for securing the design continuity at the chamfered portion.

In a preferable embodiment, the concavo-convex surface of the chamfered portion is formed into a continuous curved surface. By forming the chamfered portion into such a continuous curved surface, a shade almost similar to the shade formed on the embossed pattern constituting the surface pattern can be more assuredly formed on the chamfered portion when light is applied from the oblique direction. As a result, a viewer can recognize as if the right and left embossed patterns are continued, thereby making the chamfered portion less conspicuous, in combination with the narrow width, resulting in a great looking corner formative member.

In the corner formative member according to the present invention, it is preferable that a width of the adhesive layer remained at the apex angle portion falls within the range of about 0.3 to 0.5 mm. In the case of using humidity hardening type urethane or epoxy system adhesive, the applied adhesive will be impregnated in the plate pieces, and therefore almost no adhesive layer will be formed at the bonded surfaces of the apex angle portion. Even if it is formed, it will be about 0.1 mm or less. In the case of using reactive hot melt adhesive, the aforementioned adhesive layer will be formed with a visible thickness. If the thickness of the formed adhesive layer is thinner than about 0.3 mm, sufficient bonding ability cannot be obtained. On the other hand, if it exceeds about 0.5 mm, it becomes an over specification.

In the corner formative member according to the present invention, the maximum width of the chamfered portion with a narrow width is preferably about 8 mm or less, more preferably about 2 to 5 mm, still more preferably about 2 to 3 mm, in view of the dripping at the time of the post-painting and/or the cracking at the time of the working. Narrowing the width further enhances the continuity of the pattern design of the right and left plate members.

The present invention also discloses an apparatus for chamfering the apex angle portion of the corner formative member. That is, an apparatus for chamfering an apex angle portion of a corner formative member, comprises:

a corner formative member supporting means configured to support the corner formative member formed by bonding at least two plate pieces via reactive hot melt adhesive so as to form an apex angle portion extending in a longitudinal direction;

a rotation cutting tool disposed so as to intersect with the apex angle portion of the supported corner formative member;

a rotation cutting tool supporting means configured to support the rotation cutting tool in a vertically movable manner along a concavo-convex surface formed at the apex angle portion;

a transporting means configured to give a relative movement between the rotation cutting tool and the corner formative member; and

a cooling means configured to cool a region where the apex angle portion of the corner formative member is cut with the rotation cutting tool.

In the apparatus, since the rotation cutting tool is supported in a vertically movable manner along the concavo-convex surface formed on the apex angle portion with the posture intersecting with the apex angle portion of the corner formative member supported by the supporting means, when a relative movement is generated between the corner formative member and the rotation cutting tool, the cutting (chamfering work) is advanced on the apex angle portion along the concavo-convex surface. Therefore, the chamfered portion will be formed into a shape with a narrow width extending along the concavo-convex side of the apex angle portion.

When the rotation cutting tool cuts the apex angle portion of the corner formative member at a high revolution speed, frictional heat will be generated. In the apparatus according to the present invention, however, a cooling means for cooling the region where the apex angle portion of the corner formative member is being cut with the rotation cutting tool is equipped. Therefore, by the cooling effect of the cooling means, it becomes possible to prevent the reactive hot melt adhesive from re-softening (dissolving) by the frictional heat. Even if the exposed surface is slightly re-softened, it will be hardened promptly. Therefore, the re-softened adhesive surface portion will not be cut. Even if it is cut, it is possible to prevent the cut pieces from being involved in the rotation cutting tool. Thereby, the cut surface, i.e., the end face (exposed surface) of the adhesive layer remaining at the bonded portion of the apex angle portion at the side of the chamfered portion, will be always maintained as a flat surface cut by the rotation cutting tool, in the same manner as in the case of using a conventional humidity hardening type adhesive such as humidity hardening type urethane adhesive.

Only one cooling means can be provided at one location near the rotation cutting tool. In this case, a big capacity cooling means will be required. To avoid it, a second cooling means provided at an upstream side of a region where the apex angle portion of the corner formative member is cut with the rotation cutting tool and capable of cooling the region where the apex angle portion of the corner formative member is to be cut with the rotation cutting tool can be further provided.

Moreover, immediately after the cutting, re-softening may slightly occur at the reactive hot melt adhesive. To avoid it, a third cooling means provided at a downstream side of a region where the apex angle portion of the corner formative member is cut with the rotation cutting tool and capable of cooling the region where the apex angle portion of the corner formative member was cut with the rotation cutting tool can be further provided.

In the apparatus according to the present invention, two or more rotation cutting tools can be arranged in a longitudinal direction of the corner formative member to be cut. By disposing rotation cutting tools at plural stages, it becomes possible to reduce the load per one rotation cutting tool, resulting in stable working, extended life of the ration cutting tool and a further flattened cut surface. By setting the cutting blade pitch of the rotation cutting tool of each stage to be the largest at the first stage and then smaller in order, more stabilized chamfering work can be performed. In the case of arranging rotation cutting tools at multiple stages, it is preferable that cooling means are provided near the rotation cutting tool of each stage at the upstream side and the downstream side. In the case of providing two or more stages of the rotation cutting tools, it is preferable to equally set the cutting height level of the rotation cutting tool of each stage. If the cutting level of the rotation cutting tool at the lower stage side is positioned lower than the cutting level of the higher stage side, the cut surface of the adhesive layer will appear again, which prevents the smooth removal of the adhesive.

The cooling means can be any means so long as it can remove the frictional heat to be generated. However, it is necessary that the cooling means can lower the temperature of the cutting region below the softening point of the reactive hot melt adhesive (generally, 80 to 90° C.). From the viewpoint of the simplicity and the handling-easiness of an apparatus, it is preferable that it is a means for blowing air to the cooling region. It is more preferable to further provide a means for pre-cooling air and blowing the cooled air. As an example, a cooled pressurized air apparatus using expansion of air, called air cool, can be exemplified. This is an apparatus capable of supplying cooled pressurized air of a temperature of about −7 to −40° C. and a pressure of about 0.3 to 0.7 MPa. By blowing the cooled pressurized air to the cutting region, the chamfered portion will be cooled and the cut chips on the chamfered portion will be blown away.

In the apparatus according to the present invention, as the rotation cutting tool, any cutting tool can be used so long as it can move along an irregular continuous concavo-convex surface formed on the apex angle portion of the corner formative member while executing the cutting. However, the rotation cutting tool is preferably a grinder bit driven by compressed air. The cutting blade can be of any shape, such as, e.g., a spiral bit shape with a helix angle or a cross-bit shape.

THE EFFECT OF THE INVENTION

According to the present invention, in a corner formative member in which two plate pieces are bonded via reactive hot melt adhesive, it is possible to make the chamfered portion at the apex angle portion of the corner formative member less conspicuous and as small as possible. Furthermore, it is also possible to form a shade similar to the shade generated on the surface embossed pattern on the chamfered portion, which makes it possible to provide a corner formative member with a chamfered portion without a strange appearance.

The above and/or other aspects, features and/or advantages of various embodiments will be further appreciated in view of the following description in conjunction with the accompanying figures. Various embodiments can include and/or exclude different aspects, features and/or advantages where applicable. In addition, various embodiments can combine one or more aspect or feature of other embodiments where applicable. The descriptions of aspects, features and/or advantages of particular embodiments should not be construed as limiting other embodiments or the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiments of the present invention are shown by way of example, and not limitation, in the accompanying figures, in which:

FIG. 1(a) is a side view showing a corner formative member according to an embodiment of the present invention;

FIG. 1(b) is a cross-sectional view taken along the line b-b in FIG. 1(a);

FIG. 1(c) is an enlarged perspective view showing a principal part of the corner formative member;

FIG. 2 is a view realistically showing the corner formative member as seen from above;

FIG. 3 is a view realistically showing a conventional corner formative member to which chamfering work was executed by a conventional production method, which corresponds to FIG. 2;

FIG. 4 is a side view showing a corner formative member before executing the chamfering work;

FIG. 5 is a side view for explaining an embodiment of a chamfering work method according to the present invention;

FIG. 6 is a perspective view showing a principal part of an apparatus for chamfering an apex angle portion of a corner formative member according to the present invention;

FIG. 7 is a side view of the apparatus shown in FIG. 6 as seen from the traveling direction of the corner formative member;

FIG. 8 is a schematic side view of the apparatus shown in FIG. 6;

FIG. 9 is a perspective view showing an example of a conventional corner formative member;

FIGS. 10(a) to 10(d) are explanatory views for explaining an example of steps for making a corner formative member conventionally; and

FIG. 11 is a schematic view showing a conventional chamfered portion of a corner formative member using reactive hot melt adhesive.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following paragraphs, some preferred embodiments of the invention will be described with reference to the attached drawings by way of example and not limitation. It should be understood based on this disclosure that various other modifications can be made by those in the art based on these illustrated embodiments.

Hereafter, the present invention will be explained with reference to the attached drawings. FIG. 1 shows a corner formative member A according to an embodiment of the present invention, wherein FIG. 1(a) is a side view showing the corner formative member, FIG. 1(b) is a cross-sectional view taken along the line b-b in FIG. 1(a), and FIG. 1(c) is an enlarged perspective view showing a principal part of the corner formative member. FIG. 2 shows the corner formative member more realistically as seen from above, FIG. 3 is a view showing a corner formative member to which chamfering work was executed by a conventional production method, which corresponds to FIG. 2, FIG. 4 is a side view showing a corner formative member before executing the chamfering work, FIG. 5 is a side view for explaining an example of a chamfering work method according to the present invention, and FIG. 6 is a perspective view showing a principal part of an apparatus for chamfering an apex angle portion of a corner formative member according to the present invention, FIG. 7 is a side view of the apparatus shown in FIG. 6 as seen from the traveling direction of the corner formative member, and FIG. 8 is a schematic side view of the apparatus shown in FIG. 6.

In this embodiment, each of the plate pieces 1 a and 1 a constituting a corner formative member A has an embossed pattern including convex ridges 6 and concave grooves 7 extending in a direction intersecting with the bonded surface. These two plate pieces 1 a and 1 a are bonded with each other in such a manner that the corresponding sides thereof form an apex angle portion 3 along the longitudinal direction with the concavo-convex embossed pattern (repeating patterns of the convex ridges 6 and the concave grooves 7) in conformity with each other at the apex angle portion 3. Thus, the apex angle portion 3 has a concavo-convex surface continuing in accordance with the concavo-convex design of the embossed pattern. For bonding the plate pieces 1 a and 1 a, reactive hot melt adhesive P is used. As shown in FIG. 1(c), the reactive hot melt adhesive P remains as an adhesive layer between the bonded surfaces. The adhesive layer is about 0.3 to 0.5 mm in thickness. The use of reactive hot melt adhesive P can shorten the period of time required for the stable bonding of the two plate pieces 1 a and 1 a, thereby improving the manufacturing efficiency.

In this embodiment, for the purpose of attaining excellent design appearance, the two plate pieces 1 a and 1 a are formed to be slightly different with each other in the shape of each of the convex ridges 6 and concave grooves 7. The average distance “a” between the adjacent ridges of the convex apexes (see FIG. 1) is about 10 to 15 mm, and the average height between the bottom of the concave groove 7 and the apex of the convex ridge 6 is about 8 mm. In cases where a simple repeating design is desired, convex ridges of the same shape and concave grooves of the same shape can be arranged alternatively, though not illustrated.

As shown in FIG. 4 illustrating the bonded state, since the misalignment between the two plate pieces 1 a and 1 a and/or the protruded adhesive Pa of reactive hot melt adhesive P may occur at the apex angle portion 3 of the corner formative member A, chamfering work is given to the apex angle portion 3 along with the concavo-convex pattern thereof using an apparatus which will be explained later. As a result, as shown in FIG. 5, the misalignment portion and/or the protruded adhesive Pa of reactive hot melt adhesive P are removed from the apex angle portion 3, and therefore the chamfered portion 8 with a narrow width is formed at the apex angle portion 3. Thus, as shown in FIG. 1(c), the end face Pc of the adhesive P at the side of the chamfered portion 8 becomes a flat surface extending along the concavo-convex surface of the chamfered portion 8. This result in a stabilized minute coating film 10 with no irregularity on the chamfered portion 8 given by post-painting. Thus, the coating film 10 to be formed by post-painting has a stable surface with no minute irregularity.

In the embodiment shown in FIG. 1, the apex angle portion 3 is chamfered so that the convex portion region of the embossed pattern at the apex angle portion (the portions where the convex ridges 6 are joined) and the concave portion region of the embossed pattern at the apex angle portion (the portions where the concave grooves 7 are joined) constitute continuous curved surfaces 8 a and 8 b, resulting in a narrow chamfered portion 8. However, the concave portion region is not always required to be chamfered as mentioned above. It is preferable that the width of the chamfered portion 8 is narrow, e.g., about 8 mm or less. As mentioned above, post-painting is given to the narrow chamfered portion 8. Thus, a corner formative member A can be obtained.

In the corner formative member A according to this embodiment, the chamfered portion 8 is formed into a generally narrow width and has a stabilized coating film 10 formed by post-painting, and the convex portion region of the embossed pattern forms a continuous curved surface 8 a at at least the apex angle portion 3. Therefore, as shown in FIG. 2, the entire chamfered portion 8 becomes less conspicuous, and sunlight portions and shade portions, which are similar to the sunlight portions S and the shade portions D generated on the surface pattern of the plate pieces 1 a and 1 a under the daytime sunlight, also generated on the continuous curved surface 8 a of the chamfered portion 8. As a result, the sunlight portion S and the shade portion D of the right and left plate pieces 1 a and 1 a look continuous. Accordingly, a viewer can recognize such that the embossed patterns of the plate pieces 1 a and 1 a are continued as a whole, resulting in a much less conspicuous chamfered portion.

FIG. 3 shows a case in which the apex angle portion 3 of the corner formative member A1 consisting of the same plate pieces 1 a and 1 a of the corner formative member A shown in FIGS. 1 and 2 is chamfered with a conventional Tenoner cutting machine. In this case, the chamfered portion 8 (Sa) having a rhombus-shaped flat face, as illustrated, is formed every apex angle portion of each convex ridge 6. Even if a coating film is formed on this chamfered portion by post-painting, the coating film portion of the corner formative member A1 forms a large sunlight region Sa under daytime sunlight, with conspicuous appearance, which gives strange appearance. Furthermore, the shade portions D of the convex ridges 6 of the right and left plate pieces 1 a and 1 a are discontinued at the portion, resulting in a discontinued design. To the contrary, in the corner formative member A according to the embodiment, the aforementioned inconvenience has been solved.

Now, an example of an apparatus B for use in manufacturing the aforementioned corner formative member A, i.e., an apparatus for chamfering the apex angle portion 3 of the corner formative member formed by bonding sides of the two plate pieces 1 a and 1 a using reactive hot melt adhesive P so as to form the apex angle portion 3 extending along the longitudinal direction as shown in FIG. 5, will be explained with reference to FIGS. 6 to 8.

This apparatus B includes a corner formative member supporting means 20 equipped with feed rollers 21, a rotation cutting tool 30 (preferably grinder bit) located so as to intersect with the apex angle portion 3 of the corner formative member A supported by the corner formative member supporting means 20, a rotation cutting tool supporting means 40 for supporting the rotation cutting tool 30 in a vertically movable manner along the concavo-convex pattern formed on the apex angle portion 3, a transferring means for giving a relative movement between the rotation cutting tool 30 and the corner formative member A, and a cooling means 50 for cooling the region where the apex angle portion 3 of the corner formative member A is cut with the rotation cutting tool 30.

In this embodiment, it is configured such that the feed rollers 21 provided at the corner formative member supporting means 20 moves the corner formative member A to give a relative movement between the rotation cutting tool 30 and the corner formative member A. The feed roller 21 also serves as a transferring means according to the present invention. However, it can be configured such that the rotation cutting tool 30 is moved by any moving means with the corner formative member A supported by the corner formative member supporting means 20 fixed. In the illustrated embodiment, the corner formative member supporting means 20 is provided with a plurality of feed rollers 21 arranged in a horizontal direction and a flat belt 22 put on the entire feed rollers 21 so as to stabilize the feeding operation. However, this flat belt 22 can be omitted. Furthermore, although the rotation cutting tool 30 and the rotation cutting tool supporting means 40 are placed at two portions in the moving direction (longitudinal direction) of the corner formative member A, they can be placed at one portion, or three or more portions.

A corner formative member A formed by bonding the sides of two plate pieces 1 a and 1 a using reactive hot melt adhesive P so as to form an apex angle portion 3 extending in the longitudinal direction as described above is put on the feed rollers 21 with the apex angle portion 3 faced upward. With this state, in accordance with the rotation of the feed rollers 21, the corner formative member A is moved in the direction of the arrow X. In order to stabilize the transferring of the corner formative member A, it is preferable to provide pressing rollers 23.

In this embodiment, the rotation cutting tool 30 is a grinder bit with a helix-angle α, and can be of, e.g., a spiral-bit shape or cross-bit shape. In each case, the helix-angle α should be about 45° or less, preferably falls within the range of about 10° to 30°. The rotation cutting tool 30 is preferably a super hard blade bit. In cases where the grinder bits 30 are placed at two stages as illustrated, it is preferable that the helix-angle α of the grinder bit 30 located at the cutting upstream side is about 10° and the helix-angle α of the grinder bit 30 located at the cutting downstream side is about 30°. The rotation cutting tool 30 preferably has a diameter capable of entering in the concave portion of the concavo-convex portion formed on the apex angle portion 3 and moving along the concave portion. For example, in cases where the corner formative member A in which the distance between the adjacent apexes of convex ridges is about 10 to 15 mm like the corner formative member A shown in FIG. 1 is chamfered, a rotation cutting tool (grinder bit) 30 with a diameter of about 3 to 4 mm is used.

These two rotation cutting tool supporting means 40 are the same in structure, and each has a supporting post 42 upwardly protruded from a fixed machine frame 41 and a movable machine frame 43 attached to the supporting post 42 in a vertically movable manner. Between the fixed machine frame 41 and the movable machine frame 43, a coil spring 45 is disposed so as to surround the supporting post 42. The movable machine frame 43 is for giving a prescribed load required for the cutting operation to the rotation cutting tool 30 against the coil spring 45. The movable machine frame 43 having an appropriate weight is selected depending on the actual machine.

The movable machine frame 43 is equipped with a pneumatic rotating apparatus 46 connected to a pneumatic source (not shown). As best shown in FIG. 7, at the tip of the pneumatic rotating apparatus 46, the rotation cutting tool 30 is attached with the rotation axis C arranged horizontally. As shown in FIG. 7, the rotation axis C of the rotation cutting tool 30 is set to be perpendicular to the traveling direction X (see FIG. 6) of the corner formative member A, and the cutting blade is disposed so as to touch the apex angle portion 3 of the traveling corner formative member A with the rotation axis C perpendicularly intersected with the ridgeline of the apex angle portion 3.

The strength (spring constant) of the coil spring 45 disposed between the fixed machine frame 41 and the movable machine frame 43 is preferably set such that when the movable machine frame 43 is placed on the coil spring 45 in a free state, the level L1 of the lowest side of the rotation cutting tool 30 is positioned slightly lower than the level L2 of the bottom of the concave groove 7 forming the ridgeline of the apex angle portion 3 of the traveling corner formative member A as shown in FIG. 5. In cases where two rotation cutting tool supporting means 40 and 40 are provided like in the illustrated embodiment, the level L1 of the lowest side of each rotation cutting tools 30 and 30 is set to be the same level L1.

In this embodiment, the cooling means 50 uses air as heat exchanging fluid, and is configured to spout a prescribed amount of pre-cooled air from a nozzle 51 through a pump P and piping 52. Preferably, a cooled pressurized air apparatus using expansion of air, called air cool, is used. For example, cooled and pressurized air is blown through the nozzle 51 at the temperature of about −7° C. to −18° C. and the pressure of about 0.3 Mpa to 0.7 MPa. The nozzle 51 is placed at at least the position 51 a where air can be blown against the region where the rotation cutting tool 30 is cutting the apex angle portion 3 of the corner formative member A as shown in FIG. 8. It is more preferable that the second and third nozzles 51 are provided at the upstream side and the downstream side of the region cut by the rotation cutting tool 30. At the time of the chamfering work, the nozzle 51(51 a) spouts an amount of pre-cooled air which can prevent the re-softening (dissolution) of the reactive hot melt adhesive P used to bond the corner formative member A by the frictional heat produced by the cutting of the apex angle portion 3 with the rotation cutting tool 30. By this blowing pre-cooled air, the rotation cutting tool 30 will also be cooled and the cut pieces will be blown away.

In executing the chamfering work, compressed air is fed to the pneumatic rotating apparatus 46 to rotate the rotation cutting tool 30 at a prescribed rotation rate (e.g., about 25,000 rpm). When the corner formative member A is transferred using the corner formative member supporting means 20, since each movable machine frame 43 is upwardly urged by the coil spring 45, the two rotation cutting tools 30 and 30 can independently move upward and therefore can move up and down in accordance with the concavo-convex face generated on the ridgeline of the apex angle portion 3 of the corner formative member. Thus, the rotation cutting tool 30 executes the chamfering along the concavo-convex generated on the ridgeline of the apex angle portion 3. As a result, a chamfered portion 8 with a narrow width is formed simultaneously with the scraping of the protruded adhesive Pa.

During the process, pre-cooled air is consecutively being blown from the nozzle 51 of the cooling means 50 to thereby cool the cutting region and the front and rear regions thereof. Therefore, re-softening of the reactive hot melt adhesive P due to the frictional heat would not occur, and adhering and clinging of the reactive hot melt adhesive P to the rotation cutting tool 30 also would not occur. Accordingly, as described above and shown in FIG. 1(c), the end face Pc where the reactive hot melt adhesive P is exposed to the chamfered portion 8 side becomes a flat surface extending along the concavo-convex surface of the chamfered portion 8.

In the illustrated embodiment, the coil spring 45 is disposed between the fixed machine frame 41 and the movable machine frame 43 to adjust the downward load of the rotation cutting tool 30 acting on the apex angle portion 3 of the corner formative member A. However, it should be recognized that prescribed chamfering work can be performed by simply adjusting the weight of the movable machine frame 43 without using the coil spring 45.

While the present invention may be embodied in many different forms, a number of illustrative embodiments are described herein with the understanding that the present disclosure is to be considered as providing examples of the principles of the invention and such examples are not intended to limit the invention to preferred embodiments described herein and/or illustrated herein.

While illustrative embodiments of the invention have been described herein, the present invention is not limited to the various preferred embodiments described herein, but includes any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., of aspects across various embodiments), adaptations and/or alterations as would be appreciated by those in the art based on the present disclosure. The limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive. For example, in the present disclosure, the term “preferably” is non-exclusive and means “preferably, but not limited to.” In this disclosure and during the prosecution of this application, means-plus-function or step-plus-function limitations will only be employed where for a specific claim limitation all of the following conditions are present in that limitation: a) “means for” or “step for” is expressly recited; b) a corresponding function is expressly recited; and c) structure, material or acts that support that structure are not recited. In this disclosure and during the prosecution of this application, the terminology “present invention” or “invention” is meant as a non-specific, general reference and may be used as a reference to one or more aspect within the present disclosure. The language present invention or invention should not be improperly interpreted as an identification of criticality, should not be improperly interpreted as applying across all aspects or embodiments (i.e., it should be understood that the present invention has a number of aspects and embodiments), and should not be improperly interpreted as limiting the scope of the application or claims. In this disclosure and during the prosecution of this application, the terminology “embodiment” can be used to describe any aspect, feature, process or step, any combination thereof, and/or any portion thereof, etc. In some examples, various embodiments may include overlapping features. In this disclosure and during the prosecution of this case, the following abbreviated terminology may be employed: “e.g.” which means “for example;” and “NB” which means “note well.” 

1. A corner formative member, comprising: at least two plate pieces bonded with each other at side portions thereof via reactive hot melt adhesive so as to form an apex angle portion extending in a longitudinal direction, wherein a chamfered portion with a narrow width is formed on the apex angle portion, wherein the chamfered portion is formed into a longitudinally extended non-horizontal irregularly arranged continuous concavo-convex surface, and wherein an adhesive layer remains at a joint portion of the apex angle portion and an end face of the adhesive layer at the chamfered side portion is a flat surface along the concavo-convex surface of the chamfered portion.
 2. The corner formative member as recited in claim 1, wherein the plate piece has an embossed pattern as a surface pattern extending in a direction intersecting with a joint face of the plate piece.
 3. The corner formative member as recited in claim 1, wherein the concavo-convex surface of the narrow chamfered portion formed on the apex angle portion includes a continuous curved portion.
 4. The corner formative member as recited in claim 1, wherein a width of the adhesive layer remained at the apex angle portion falls within the range of about 0.3 mm to about 0.5 mm.
 5. The corner formative member as recited in claim 1, a width of the narrow chamfered portion formed on the apex angle portion is 8 mm or less.
 6. The corner formative member as recited in claim 1, wherein post-painting is applied to the chamfered portion.
 7. An apparatus for chamfering an apex angle portion of a corner formative member, comprising: a corner formative member supporting means configured to support the corner formative member formed by bonding at least two plate pieces via reactive hot melt adhesive so as to form an apex angle portion extending in a longitudinal direction; a rotation cutting tool disposed so as to intersect with the apex angle portion of the supported corner formative member; a rotation cutting tool supporting means configured to support the rotation cutting tool in a vertically movable manner along a concavo-convex surface formed at the apex angle portion; a transporting means configured to give a relative movement between the rotation cutting tool and the corner formative member; and a cooling means configured to cool a region where the apex angle portion of the corner formative member is cut with the rotation cutting tool.
 8. The apparatus as recited in claim 7, further comprising a second cooling means provided at an upstream side of a region where the apex angle portion of the corner formative member is cut with the rotation cutting tool, the second cooling means being configured to cool at least the region where the apex angle portion of the corner formative member is to be cut with the rotation cutting tool.
 9. The apparatus as recited in claim 8, further comprising a third cooling means provided at a downstream side of a region where the apex angle portion of the corner formative member was cut with the rotation cutting tool, the third cooling means being configured to cool at least the region where the apex angle portion of the corner formative member was cut with the rotation cutting tool.
 10. The apparatus as recited in claim 7, wherein two or more rotation cutting tools are arranged in a longitudinal direction of the corner formative member to be cut.
 11. The apparatus as recited in claim 7, wherein the cooling means is for blowing air or pre-cooled air to the cooling region.
 12. The apparatus as recited in claim 7, wherein the rotation cutting tool is a grinder bit driven by compressed air.
 13. The corner formative member as recited in claim 2, wherein the concavo-convex surface of the narrow chamfered portion formed on the apex angle portion includes a continuous curved portion.
 14. The corner formative member as recited in claim 2, wherein a width of the adhesive layer remained at the apex angle portion falls within the range of about 0.3 mm to about 0.5 mm.
 15. The corner formative member as recited in claim 3, wherein a width of the adhesive layer remained at the apex angle portion falls within the range of about 0.3 mm to about 0.5 mm.
 16. The corner formative member as recited in claim 2, a width of the narrow chamfered portion formed on the apex angle portion is 8 mm or less.
 17. The corner formative member as recited claim 3, a width of the narrow chamfered portion formed on the apex angle portion is 8 mm or less.
 18. The corner formative member as recited in claim 4, a width of the narrow chamfered portion formed on the apex angle portion is 8 mm or less.
 19. The apparatus as recited in claim 8, wherein two or more rotation cutting tools are arranged in a longitudinal direction of the corner formative member to be cut.
 20. The apparatus as recited in claim 9, wherein two or more rotation cutting tools are arranged in a longitudinal direction of the corner formative member to be cut. 